Abstract
Background: Dermatophytes are non-motile filamentous fungi prevalent in tropical regions and are primarily diagnosed based on clinical presentation. However, KOH mount and fungal culture detection improve diagnostic accuracy and guide further treatment.
Aim: To correlate the diagnostic performance of KOH with mycological culture in clinically suspected patients of tinea corporis.
Method: A cross-sectional study was conducted in the Department of Microbiology, Basic Medical Sciences Institute, Karachi, from June 2018 to June 2019. A total of 301 samples were collected using a non-probability convenience sampling technique after informed consent was obtained from all participants. Collected samples were examined with a KOH mount and fungal culture. Data were analyzed using the Statistical Package for Social Sciences (SPSS), version 21. Sensitivity, specificity, PPV, NPV, and diagnostic accuracy were calculated using culture as the gold standard.
Results: A total of 301 samples were analyzed to compare the performance of the KOH mount with fungal culture. Among these, 136 samples were culture-positive (84 dermatophytes, 52 non-dermatophytes), while 165 were culture-negative. KOH mount detected fungal elements in 208 samples and was negative in 93 samples. The KOH mount demonstrated a sensitivity of 76.5% and a specificity of 36.9%. The positive predictive value (PPV) was 50.0%, while the negative predictive value (NPV) was 65.6%. Overall, the accuracy of the KOH mount in detecting fungal elements was 55.5%.
Conclusion: KOH mount is a rapid and cost-effective screening tool, while culture remains essential for confirmation, species identification, and treatment guidance when results are uncertain.
Keywords
Tinea corporis, Dermatophytes, KOH mount, Fungal culture, Diagnostic accuracy